This invention relates to a safety pedal for bicycles, of the type comprising a device for quick coupling to a cleat fastened to the sole of a shoe, including a toe element for receiving a front end of the cleat and a rear fastening device, which is suitable for engaging the rear end of the cleat when this is pressed over said rear fastening device, and which is also suitable for releasing the cleat when this is rotated in the general plane of the pedal in such a way that its rear end moves laterally, said pedal comprising a flat resting surface for the cleat, including cam means for opposing said releasing rotation of the cleat and for lifting the side of the cleat which is moved away from the center of the pedal when said releasing rotation is imposed on the cleat.
A pedal of the type described above is disclosed, for example, in Italian patent no. 1,257,143, in the corresponding French patent no. 2,697,493, in the corresponding German patent no. 4,323,575 and in the corresponding U.S. Pat. No. 5,419,218.
FIG. 1 of the accompanying drawings is identical to FIG. 1 of the above mentioned documents. The description of each of the aforesaid documents is incorporated herein by reference.
In said known pedal, the cleat 5 to be mounted on the sole of a shoe can be rapidly coupled to the pedal. For this purpose, the front end of the cleat is received in a toe element 14 of the pedal, after which the rear end of the cleat is pressed over a horizontal arm 28 of a spring 18, which thus snap locks said rear end holding it in position. In this coupling condition, the shoe can be released from the pedal by turning the foot in the general plane of the pedal so as to move the rear end of the cleat 5 towards one of its sides. Typically, the heel of the shoe is moved laterally outwards with respect to the bicycle, in the mounted condition of the pedal on a bicycle, so that the horizontal arm 28 of the spring 18 turns on the axis of the vertical arm 27, releasing thereby the cleat 5. Furthermore, in said known pedal, the resting plane of the cleat 5 over the pedal is defined by a plate 15 fastened over the body of the pedal and including two slanted tabs 40, diverging upwards, acting as means for opposing the rotation of the cleat 5 in the general plane of the pedal. More precisely, the tabs 40 cause a cam-like effect on the cleat 5 when said releasing rotation is impressed to the latter, whereby the side of the cleat 5 which is moved away from the center of the pedal during said rotation is forced by the respective tab 40 to raise upwardly. In this way, the advantages of preventing undesired releasing of the cleat from the pedal during normal use of the bicycle is obtained, because the pressure exerted by the cyclist on the pedal opposes a lifting movement of the cleat, whilst, on the other hand, releasing of the shoe from the pedal is ensured in emergency conditions, for example in the case of a fall or in any other case in which the cyclist ceases to impose pressure on the pedal.
In the above mentioned known solution, the mode of operation described above occurs both when the heel of the shoe is moved laterally outwards with respect to the bicycle, i.e. when it is moved away from the bicycle, and when the heel of the shoe is moved laterally inwards.